For more than a century, management of the Hyrcanian forests was focused on wood production. However, the selection of conservation indicators as the most important reveals a recent emphasis amongst forest managers on other functions of the Hyrcanian forests.
Most previous studies in the Hyrcanian forests prioritized indicators based on their importance. By adding measurability as an additional factor, the protection indicators showed the highest value among all Hyrcanian forest function indicators.
Only a few recreation indicators remained as important or measurable indicators, which may be attributable to the lack of strong theory and appropriate practices related to recreation.
In addition to the measurability attribute, the interconnection of indicators plays a significant role in achieving a set of key performance indicators. The indicators' overall cumulative impacts determine those with the highest centrality and were eventually assumed as the key performance indicators.
Based on the interconnections between indicators, five indicators were recognized as key performance indicators for four forest functions, consistent with a more realistic view of forest management with particular attention to the cost and effort involved in measuring indicators.
This study identifies key performance indicators for monitoring the sustainability of forest functions in the northern forests of Iran. This process was conducted in two phases through the Delphi method, and Fuzzy Cognitive Mapping (FCM). The Delphi method classified indicators according to two properties, importance and measurability. These were used to identify four classes: (a) important and measurable, (b) important and less measurable, (c) less important and measurable, (d) less important and less measurable. Indicators placed in groups (a) and (b) were then used to develop a set of key performance indicators using FCM. The FCM enabled the evaluation of the overall cumulative impacts of all indicators within the network, individually and collectively, through their interactions with other indicators. The selected methods and possible application of the key performance indicators could be used to determine how to achieve the sustainable management of a forest area.